(BIOSTATISTICS AND BIOINFORMATICS (BBC): CORE C) PROJECT SUMMARY Description: The Biostatistics and Bioinformatics Core (BBC) provides comprehensive and expert analytic tools for IDDRC users who require support in biostatistics, experimental design and/or the analysis of the large datasets culled from DNA sequencing and cognate technologies. The Core has 3 components: (1) The Biostatistics Service, reposed in the Department of Biostatistics and Epidemiology, provides support for experimental design, including the design of clinical trials and the analysis of experimental results. Dr Mary Putt, Core Director, serves as Vice-Chair of the Graduate Group in Epidemiology and Biostatistics and Graduate Program Chair for Biostatistics; (2) The Bioinformatics Service supports the analysis of gene sequences, copy number variants (CNVs) and genome-wide association studies. This effort is reposed in the Center for Applied Genomics, directed by Dr Hakon Hakonarson, a pioneer in genomics and genome-wide mapping. (3) The Mitochondrial DNA Analysis Service supports the analysis of mitochondrial DNA (mtDNA) variants through the MitoMap system (http://mitomap.org), a meticulously curated database conceived, developed and maintained by Dr Douglas Wallace (1). This effort is reposed in the Center for Mitochondrial and Epigenomic Medicine, which Dr Wallace directs. Drs. Hakonarson and Wallace now join the Intellectual and Developmental Disabilities Research Center (IDDRC) as Co-Directors of the BBC. The emphasis of the Core is to assure: (a) Stringent quality control with respect to experimental design and statistical analysis, thereby assuring that studies are properly controlled, adequately powered, cost-effective and in strict conformity with all ethical standards; (b) Unfettered and expert access to state-of-the-art bioinformatics resources for the analysis of genetic data, both nuclear and mitochondrial. Our goal is to make this expertise available to all IDDRC users, both locally and throughout the IDDRC Network. Relevance to IDDRC Mission: The BBC has been developed with careful attention to the overall theme of our IDDRC ? ?Genes, Brain and Behavior?, or the effort to understand developmental disabilities in three inter- related domains: (a) The genetic anlage which causes and/or modulates essentially all developmental disabilities; (b) The biochemical and neurophysiologic alterations which arise from genetic factors; and (c) The aberrant behaviors which we associate with these genetic and neurophysiologic changes and which we recognize as the phenotypes of developmental disabilities. The Core is integrated into multiple domains of biomedical research, from basic science to clinical translational medicine. The BBC will facilitate detailed understanding of the genetics of intellectual and developmental disabilities (IDD). It will further ensure that investigations of the phenotypic consequences of these genetic alterations are executed and analyzed according to scrupulous statistical criteria. Eligibility: These services are available both to approved users of the IDDRC at Children's Hospital of Philadelphia (CHOP)/Penn and to users at other Centers in the Network.